Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Aug. 31, 2023	Aug. 31, 2022	Aug. 31, 2021
Income Statement [Abstract]
Revenues	$ 2,085,508	$ 1,843,892	$ 1,591,445
Operating expenses
Cost of services	973,225	871,106	786,400
Selling, general and administrative	457,130	433,032	331,004
Asset impairments	25,946	64,272	0
Total operating expenses	1,456,301	1,368,410	1,117,404
Operating income	629,207	475,482	474,041
Other income (expense), net
Interest income	12,809	6,175	1,806
Interest expense	(66,319)	(35,697)	(8,200)
Other income (expense), net	8,257	(2,366)	(30)
Total other income (expense), net	(45,253)	(31,888)	(6,424)
Income before income taxes	583,954	443,594	467,617
Provision for income taxes	115,781	46,677	68,027
Net income	$ 468,173	$ 396,917	$ 399,590
Basic earnings per common share (in dollars per share)	$ 12.26	$ 10.48	$ 10.56
Diluted earnings per common share (in dollars per share)	$ 12.04	$ 10.25	$ 10.36
Basic weighted average common shares (in shares)	38,194	37,864	37,856
Diluted weighted average common shares (in shares)	38,898	38,736	38,570